1. Field of the Invention
Ceramic molds are usually used as the form about which the rubber is placed for making high quality rubber gloves. The present composition is usable as a glaze about the external surface of such a ceramic mold which glaze itself is electrically conductive to facilitate the monitoring for imperfections of the gloves formed thereon. Also the conductive surface serves to increase the flow of heat to the glove to facilitate curing thereof. Preferably the conductive glaze is of a black coloration to enhance thermal retention characteristics of the mold form.
In practice a glove will be formed about a ceramic mold having the conductive glaze of the present invention therearound. Prior to removal of the glove from the form, the composite unit may be dipped in an electrolytic solution so that the conductive glaze itself will act as one electrode and another electrode may be placed in the electrolyte. In another method the glove need not be dipped in an electrolytic solution, but an electrode may be manually or otherwise caused to pass over the surface of the glove and visual arcing of a surge reading on a voltage or current meter will indicate an imperfection. In either system application of a voltage difference across the two electrodes will cause electrical current to flow between the electrodes only if an imperfection exists in the wall of the gloves at any point such that electric current may flow therethrough. However, if the glove is without imperfections the flow of current between the electrodes will be prevented. In this manner a glove can be tested for imperfections in a one-step process without requiring the removal of the glove from the mold form or the placing of the glove in a special test apparatus.
2. Description of the Prior Art
In the prior art the primary difficulty in the forming of electrically conductive glazes for ceramic mold forms was the lack of repetitive consistency of resistivity between one fired glaze and the next fired glaze. It is desirable to use a ceramic glaze having repeatably consistent surface resistivity. The prior art conductive glazes did not have this quality but the improved composition of the glaze as disclosed and claimed in the present invention provides a more repetitive consistency in surface resistivity than possible with any prior art compositions.
Particularly, the components of the glaze of the present invention are reasonably inexpensive as well as being very accessible.
Most prior art conductive surfaces on molds are achieved by using electrically conductive coatings rather than using the ceramic itself as the conducting agent. Conductive coatings tend to wear off quickly when not using the present invention but a conductive ceramic glaze has a very extended useful lifetime.